The results validated England’s approach to treating drug addicts and called for similar efforts to evaluate American drug addiction programs, according to a senior U.S. White House official.

The study looked at more than 14,600 patients across England who were addicted to either heroin, crack cocaine, or both. Researchers said the heroin addicts they observed were treated with oral methadone for at least six months between January and November 2008 and some patients also received counseling.

Cocaine addicts only received the psychological therapy since there is no recommended substitute drug treatment for crack. The study did not, however, contain a comparison between the treated addicts to those who tried to quit on their own.

Around 42 percent of heroin users reported they had stopped injecting the drug after six months, while 57 percent of crack users said they had stopped. Among those people addicted to both drugs, about half said they had either quit or cut down.

While the results were encouraging, experts said drug addicts would likely need more than six months of care.

Jeffrey Parsons, an addiction specialist at Hunter College in New York who was not linked to the research, said it is quite possible that many of those with a positive outcome experienced relapse.

Treating heroin and crack cocaine addicts is similar to managing patients with diabetes or high blood pressure, according to Dr. Thomas McLellan, deputy director of the White House’s Office of National Drug Control Policy.

McLellan said drug addicts needed continuing care just as diabetes patients wouldn’t only be treated for six months before being released without medication.

“Addiction is best thought of as a chronic condition,” McLellan said. “There is no cure, but we can manage it. Britain’s approach is an advance over similar programs in the U.S., where substance abuse treatments mostly focus on an acute period.”

Ongoing treatment would ultimately lower the medical and social costs of drug addiction, including crime and lost productivity, he added.

Britain’s National Treatment Agency for Substance Misuse funded the study. On average, it costs the government up to $7,991 per person per year to provide addiction treatment.